1. Field of the Invention
The present invention relates to a polymerizable composition and a polymer useful in various uses typically for materials for various types of optical members such as optically anisotropic films, heat insulating films, etc., and to a film using any of these.
2. Description of the Related Art
These days downsizing of liquid-crystal display devices is desired, and with that, thinning of optical films is also desired. For example, using a liquid crystal having a high Δn in an optical film such as retardation film or the like makes it possible to reduce the thickness of the film. Δn is one of important basic physical properties of a liquid-crystal compound; and a liquid crystal having a high Δn can be utilized in many industrial fields of retardation plates, polarizing elements, selective reflection films, color filters, antireflection films, viewing angle compensation films, holography, alignment films and others that are constituent elements of optical devices (Non-Patent Document 1).
Heretofore, as a liquid-crystal compound having a large Δn, there are known those having an azomethine structure such as typically MBBA (Non-Patent Document 2). One characteristic feature of a liquid-crystal compound is that the compound has flowability; but in the above-mentioned uses, the flowability of the liquid crystal may be often insufficient and the liquid crystal must be solidified while keeping the desired alignment thereof. As one solution, there is known a polymerizing liquid crystal capable of forming a network structure by introducing a bifunctional or more polyfunctional polymerizable group into a compound having an azomethine structure (Patent Document 1 and Patent Document 2).